Electric heater



Patented Sept. 2, 1924.

UNITED STATES JOHN WILSON BROWN, JR., 0F PHILADELPHIA, PENNSYLVANIA.

ELECTRIC HEATER.

Application lei March 24,

To all 'whom t may concern:

Be it known that I, J oHN WitsoN BROWN, Jr., a citizen of the United States, and resident of the city of Philadelphia, m the county of Philadelphia and State of Pennsylvania, have invented a new and useful Electric Heater, of which the following is a specification.

My invention relates to that class of apparatus in which heat is developed by the passage of electric current through a resistance.

It is the purpose of m invention to provide such a heater whic will be cheap in proportion to the maximum current which it will carry without injury, easy to manufacture,'durable, and which shall have a considerable capacity for storing heat, so

that the heating effect on the apartment to be heated may be practically constant in spite of the fact that the supply of electric current is intermittent or variable.

Referring to the drawings: Fig. l is a longitudinal sectional view of my improved heater; Fig. 2 is a cross section of same Fig. 3 is a cross section of same at B-B5 Fig. l is a longitudinal sectional View of a part of the heater showing an alternative construction of the ends.

C is a casing of copper or other metal.

Throughout the greater part of its length it is of an oval form as shown in Fig. 2, but at its ends it is cylindrical as shown in Fig. 3. It is thin so that its shape may be readily changed by the development of pressure in its interior. D is the resistance used for the conversion of the electric eur rent into heat. As shown it is a twisted strip of high resistance metal. A strip is used so as to secure a large surface. It is twisted so as to give it transverse resistance to bending. I do not confine myself to this form of resistance. Securely fastened, preferably brazed, to each end of D is a helical s ring E which is under all conditions uner tension. The purpose of these springs is to take up the differential expansion between casing C and resistance D and to facilitate the assembling of the heater. Sccurely fastened, preferably brazed, to each spring E is a plug F of brassl or some other metal. This plug has a. conical portion a and a threaded portion Securely fastened, in a manner permanently liquid tight, to each end of the casing C is a cylindrical sleeve G, having a reduced cylindrical bore 1923. Serial No. 627,258.

g and a tapered thread d. lInto this tapered thread d is screwedand sealed the nut H having a conical bore e and a fiat face f.

against this again the metal washer T. The a plug F is forcibly' drawn into the sleeve l by the nut K acting against the washer T so preventing escape of 'liquid from the interior of casing C. The nut L is used in connection with nut K to connect wires to the heater. M, M are bushings of material electrically nonconducting, such as porcelain, which prevent the resistance D from being laterally displaced in the casing C. These bushings are secured from endwise displacement by the washers N, N secured to the resistance D. The entire space, not otherwise occupied, inside the casing C is filled u ith an electrically nonconducting liquid of high boiling point such as the oil used in electric transformers.

ln operation heat is developed in resistance D by the current passing through it and this heat is communicated to the liquid which surrounds the resistance. Since the surface of D is always in contact with the liquid, its capacity for communicating heat is very large. The liquid in its turn communicatcs the heat to the casing C. Where variable er intern'iittent current is used, the body of the liquid will absorb the heat as fast as developed but, due to its heat storing capacity its temperature and consequently ils delivery of heat to the casing will vary with comparative slowness. the liquid in casing C. heated it expands and if the casing were cylindrical it would be burst by -this expansion. But :is the casing is oval in section the efl'ect is merely to deform it causing it to approximate to :i cylindrical form.

Referring to Fig'. 4. a metal boit securely fastened, preferal'ily lnfazcd, to the spring E. This bolt has a head .It and a threaded portion z'. lolt passes through two stepped bushings l, P' ot percelain or other electrically noncondiiciing material. These again rest in the nu: Q which is screwed and sealed into the sleereti. Between the head it of the `:olt O and the bushing P is an oil tight gasket R, preferably lltg . 1n permanently fixed means for of corrugated steel. Between the shoulder of bushing P and the end Of nut Q, is an oil tight packing S preferably Ot lead. Against the end of the bushing P is placed t e washer T. The nut K acting against the washer T is :forcibly screwed up causing the head of bolt O to compress the gasket R and, acting through biishin P', tlie packing S. All out-let for the liqui is thus shut Ofl.

claim-` 1. In an electric heater, an inte al casiermetica ly sealing same, a resistance within the casin and a liquid filling the casing.

2. In an electric heater, a hermetically sealed casing of Oval section of material sufficiently fiexible to permit expansion of the contained liquid, a resistance within the casin and a liquid filling said casing.

3. In an electric heater, a hermetically sealed casing of such form as to permit expansioii Of a liquid fillin it, a resistance within the casing and a iquid lling the casing.

4. In an electric heater, a casing, a resistance within the casing and means for counteracting the differential expansion between tlie resistance and the casin 5. In anelectric heater,

plug having a conical portion in On the threaded end Of the plug and a washer Of' non-conducting material between this nut and the f'ace of the lirst said nut.

6. In an electric heater, a casing having an Orifice a stopper secured to said Orifice,

7. In an electric heater, a casing having an Orifice, a stopper secured a bushing of said stopper, a

said bolt, a gasket between tlie face Of said stopper and said flange, an elastic gasket between the head Of said bolt and said flange, and means lor compressing said two pper.

l0. In an formed of a metal.

ll. In an electric heater, a resistance composed'of a twisted electric heater a resistance twisted strip of resistance a spring secured to the end of said stri and a Olt securedhto tlie end of the spr a casing tube of oval a sleeve securedv to the sleeve having a female 9m cross section, end

cylindrical bore.

JOHN WILSON BROWN, Jn. 

